JP5168192B2 - Wireless communication system and wireless communication method - Google Patents

Description

  The present invention relates to a wireless communication system and a wireless communication method.

  As a wireless connection mode related to wireless PAN (Wireless Personal Area Network), IEEE 802.15.4 defines two modes, a beacon mode and a non-beacon mode.

  In the beacon mode, the wireless relay device periodically transmits a beacon signal at a predetermined cycle, all wireless terminal devices receive the beacon signal, and the wireless terminal device operates in synchronization with the received beacon signal. Is.

  For example, a terminal device that rises from sleep mode before transmitting data, waits for reception of a beacon signal, transmits data only immediately after receiving the beacon signal, and shifts to sleep mode again when the beacon signal cannot be received is disclosed. (See Patent Document 1).

JP 2008-301006 A

  However, in the beacon mode, all wireless terminal devices periodically perform reception operations. Therefore, regardless of whether communication is necessary, the wireless terminal device periodically rises from the sleep mode and enters a wake-up state. Must receive. Therefore, there is a problem that the wireless terminal device consumes power wastefully.

  On the other hand, in the non-beacon mode, the wireless terminal device transmits a transmission request (data request signal) to the wireless relay device as necessary, and the wireless relay device transmits data according to the data request signal. Therefore, in the non-beacon mode, the wireless terminal device enters a wake-up state only when necessary, and performs communication, so that power consumption can be reduced compared to the beacon mode.

  In a star-type wireless communication system, when the same data is transmitted (broadcast) from a wireless relay device to all wireless terminal devices using the non-beacon mode, the wireless relay device uses a data request signal for each wireless terminal device. In response, data is transmitted. In this case, as the number of wireless terminal devices increases and the data size to be transmitted increases, there arises a problem that network traffic increases and communication efficiency decreases.

  As a measure for solving this problem, it can be considered that all wireless terminal apparatuses are set in a wake-up state and a reception standby state, and an address of data transmitted from the wireless relay apparatus is transmitted as a broadcast address. However, in this measure, all the wireless terminal devices must be put in a wake-up state and a reception standby state, and all the wireless terminal devices are kept in a wake-up state and a reception standby state until broadcast data transmission is completed. Therefore, there arises a problem that the power consumption of the wireless terminal device increases.

  In view of the above problems, an object of the present invention is to prevent an increase in network traffic and a decrease in communication efficiency while suppressing power consumption of a wireless terminal device when broadcasting.

  In order to solve the above-described problem, the invention according to claim 1 includes a plurality of wireless terminal devices and a wireless relay device. In a wireless communication system that performs wireless communication in a non-beacon mode, the wireless relay device includes: A first communication unit that performs wireless communication with the plurality of wireless terminal devices; and a first instruction signal that switches a wireless connection mode from the non-beacon mode to the beacon mode when transmitting to the plurality of wireless terminal devices. , Transmitting a second instruction signal for causing the plurality of wireless terminal devices to perform the broadcast after switching from the non-beacon mode to the beacon mode and for switching from the beacon mode to the non-beacon mode after the broadcast is completed. A first control unit that causes the wireless terminal device to When the first instruction signal is received from the second communication unit that performs wireless communication with the wireless relay device, the wireless connection mode is switched from the non-beacon mode to the beacon mode, and after switching to the beacon mode. And a second control unit that switches the wireless connection mode from the beacon mode to the non-beacon mode when the second instruction signal is received.

  According to a second aspect of the present invention, in the wireless communication system according to the first aspect, a beacon signal indicating that there is no data to be transmitted to the plurality of wireless terminal devices is transmitted as the first instruction signal. It is included in the message signal transmitted later.

  According to a third aspect of the present invention, in the wireless communication system according to the first or second aspect, the second instruction signal is a beacon transmitted after a beacon signal for performing the broadcast is transmitted and the broadcast is completed. It is a signal.

  According to a fourth aspect of the present invention, in the wireless communication system according to any one of the first to third aspects, the wireless relay device is a terminal in which unique information is indicated for each of the plurality of wireless terminal devices to be connected. A terminal information storage unit for storing information, wherein the first control unit acquires terminal information included in a data request signal of the wireless terminal device that has received the first instruction signal, and the terminal information storage unit When the terminal information corresponding to the terminal information stored in is acquired, it is determined that the plurality of wireless terminal devices are switched from the non-beacon mode to the beacon mode.

  According to a fifth aspect of the present invention, in the wireless communication method in which a plurality of wireless terminal devices and a wireless relay device perform wireless communication in a non-beacon mode, when the wireless relay device broadcasts to the plurality of wireless terminal devices, A first step in which a wireless relay device transmits a first instruction signal for switching a wireless connection mode from the non-beacon mode to a beacon mode; and when the wireless terminal device receives the first instruction signal, the wireless connection mode A second step of switching from the non-beacon mode to the beacon mode, and the wireless relay device causes the plurality of wireless terminal devices to perform the broadcast after switching from the non-beacon mode to the beacon mode, thereby completing the broadcast. After switching from the beacon mode to the non-beacon mode A third step of transmitting a second instruction signal, and when the wireless terminal device receives the second instruction signal after switching to the beacon mode, the wireless connection mode is changed from the beacon mode to the non-beacon mode. And a fourth step of switching to the mode.

  According to the present invention, it is possible to prevent an increase in network traffic and a decrease in communication efficiency while suppressing power consumption of a wireless terminal device when performing broadcasting.

It is a schematic block diagram of a radio | wireless communications system. It is a schematic block diagram of a radio relay apparatus. It is a figure which shows the example of a beacon frame. It is a figure which shows the example of a frame control. It is a figure which shows the example of PA field. It is a figure which shows the example of the flame | frame of broadcast data. It is a schematic block diagram of a radio | wireless terminal apparatus. It is a flowchart of the broadcast execution process performed in a radio relay apparatus. 9 is a flowchart of broadcast execution processing executed in the wireless relay device (continuation of FIG. 8). It is a flowchart of the radio | wireless connection mode switching process performed in a radio | wireless terminal apparatus. It is a sequence diagram which shows the process in which a 1st-3rd wireless terminal device switches from a non-beacon mode to a beacon mode by a wireless relay device. It is a sequence diagram which shows the process by which a broadcast is performed after the 1st-3rd radio | wireless terminal apparatus switches to beacon mode by a radio relay apparatus. It is a sequence diagram which shows the process in which a 1st-3rd wireless terminal device switches from a beacon mode to a non-beacon mode by a wireless relay device after transmission of broadcast data is completed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment. The embodiment of the present invention shows the most preferable mode of the present invention, and the terminology of the present invention is not limited to this.

First, the configuration will be described.
FIG. 1 shows a schematic configuration diagram of a wireless communication system A in the present embodiment.
As shown in FIG. 1, a wireless communication system A includes a wireless relay device 1 connected to another wireless relay device or an external device via a communication network N, and a plurality of wireless relay devices 1 connected to the wireless relay device 1 via wireless communication. Wireless terminal device 2 and performs wireless communication in a non-beacon mode.

  The wireless communication system A in the present embodiment is a wireless PAN that conforms to the IEEE 802.15.4 standard. In this case, the wireless relay device 1 corresponds to a PAN coordinator, and the wireless terminal device 2 corresponds to a network device.

FIG. 2 shows a schematic configuration diagram of the wireless relay device 1.
As shown in FIG. 2, the wireless relay device 1 includes a control unit 10, a storage unit 11, a terminal information memory 12, a beacon transmission timer 13, a wireless transmission unit 14, a wireless reception unit 15, a SW (switching unit) 16, an I An / F (InterFace) unit 17, a buffer 18, an antenna 19 and the like are provided, and each unit is electrically connected.

  The control unit 10 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The control unit 10 reads programs, tables, and data specified from various programs, various tables, data, and the like stored in the storage unit 11 and the terminal information memory 12, and is used for RAM or the storage unit 11 and terminal information. The data is expanded in the work area of the memory 12, and various processes are executed in cooperation with the program. The processing results are stored in the RAM or a predetermined area of the storage unit 11 or the terminal information memory 12, and the wireless relay device 1 is instructed to control the overall operation of the wireless relay device 1.

  In addition, the control unit 10 reads out the broadcast execution processing program stored in the storage unit 11 and various necessary data, terminal information stored in the terminal information memory 12, and the like, and executes the broadcast execution processing, so that the first Functions as a control unit.

  In the broadcast execution process, when broadcasting is performed to a plurality of wireless terminal devices connected to the wireless relay device 1, the first instruction signal is transmitted, and the plurality of wireless terminal devices are switched from the non-beacon mode to the beacon mode. The broadcast is performed later, and the second instruction signal is transmitted after the broadcast is completed.

  The first instruction signal is a signal indicating an instruction (beacon switching instruction) for switching the wireless connection mode of the wireless terminal device from the non-beacon mode to the beacon mode. The first instruction signal in this embodiment is transmitted after a beacon signal (frame pending = 0, pending address specification = 0) indicating that there is no data to be transmitted to all wireless terminal devices. Included in the message signal.

  The second instruction signal is a signal for switching the wireless connection mode of the wireless terminal device from the beacon mode to the non-beacon mode. The second instruction signal in the present embodiment is a beacon signal (frame pending = 0) transmitted after a beacon signal (frame pending = 1, pending address specification = 0) for broadcasting is transmitted and broadcast is completed. Pending address specification = 0).

  When the broadcast execution process is executed, the control unit 10 periodically generates a beacon signal, and causes the wireless transmission unit 14 to periodically transmit the generated beacon signal. The beacon signal is a packet transmitted from the wireless relay device 1 at regular intervals, and is for synchronizing the wireless terminal device 2 and the wireless relay device 1 connected to the wireless communication system A, respectively.

FIG. 3 shows an example of a beacon frame in the present embodiment.
As shown in FIG. 3, the beacon signal has an MHR (MAC (Media Access Control) header) region B1, a MAC payload region B2, and an MFR (MAC Footer) region B3.

  The MHR area B1 includes a frame control B11, an address area B12, and the like. The MAC payload area B2 includes an SS (Superframe Specification) B21, a GTS (Guaranteed Time Slot) field B22, a PA (Pending Address) field B23, a beacon payload B24, and the like.

FIG. 4 shows an example of the frame control B11.
As shown in FIG. 4, the frame control B11 includes a frame type B11a, a frame pending B11b, an ACK request B11c, a PAN ID compression B11d, a frame version B11e, and the like.
When the frame pending B11b is 0, it indicates that there is no data to be transmitted to all the wireless terminal devices, and when it is 1, there is data to be transmitted to any of the wireless terminal devices. Is shown.

FIG. 5 shows an example of the PA field B23.
As shown in FIG. 5, the PA field B23 includes an area indicating a pending address specification (pending address specification area) B23a and an address list B23b.
The pending address specification area B23a includes a number Bof area B23a1, a number of extended address pending area B23a2, and the like. The pending address specification area B23a includes information on a wireless terminal device that is a data transmission destination from the wireless relay device. When the pending address specification area B23a is 0, it indicates that there is no wireless terminal device as a data transmission destination.

  FIG. 6 shows an example of a frame of broadcast data when broadcasting is performed. As shown in FIG. 6, the broadcast data frame has an MHR region D1, a MAC payload region D2, and an MFR region D3.

  The MHR area D1 includes a frame control D11, an address area D12, and the like. The MAC payload area D2 includes a data payload D21, and stores data when broadcasting to the data payload D21.

  The address area D12 includes a destination PAN ID area D12a, a destination address area D12b, a transmission source PAN ID area D12c, a transmission source address area D12d, and the like. When broadcast is executed, a broadcast address (0xFFFF) is set in the destination address area D12b.

  The storage unit 11 includes a nonvolatile memory that can be electrically erased and rewritten, such as a magnetic or optical recording medium or a semiconductor. The storage unit 11 is fixedly attached to the wireless relay device 1 or is detachable. It is to be attached. The storage unit 11 stores in advance various programs executed by the control unit 10 and various tables and data used by these programs.

  The terminal information memory 12 is composed of a memory that can be electrically erased and rewritten. The terminal information memory 12 stores terminal information such as a node address indicating information unique to each of the wireless terminal devices 2 connected to the wireless relay device 1 and functions as a terminal information storage unit.

  The beacon transmission timer 13 is a timer for measuring the transmission interval of the beacon signal, and outputs a beacon transmission timing signal indicating that the measured time has reached the transmission interval (beacon transmission timing) to the control unit 10.

  The wireless transmission unit 14 includes a modulation circuit, an RF (Radio Frequency) circuit, and the like, adjusts the transmission power of the packet, encodes the data to be transmitted in accordance with an instruction from the control unit 10, and transmits the packet. The packet is modulated, and the packet is transmitted to the wireless terminal device 2 via the antenna 19.

  The wireless receiving unit 15 includes a demodulation circuit, an RF circuit, and the like, and is obtained by adjusting the reception sensitivity of the packet, demodulating the packet received via the antenna 19, and analyzing the demodulated packet. The data is output to the control unit 10.

  The SW 16 is provided between the antenna 19 and the wireless transmission unit 14 or the wireless reception unit 15, and transmits a packet from the wireless transmission unit 14 or receives a packet from the antenna 19 in accordance with an instruction from the control unit 10. Switch.

  The I / F unit 17 performs communication control for performing communication with another wireless relay device 1 or an external device connected via the communication network N by a predetermined communication method.

  The buffer 18 temporarily stores data received via the wired I / F 17.

  The antenna 19 transmits a packet according to the set transmission power or receives a packet according to the set reception sensitivity. The wireless transmission unit 14, the wireless reception unit 15, the SW 16, and the antenna 19 implement a first communication unit that performs wireless communication with a plurality of wireless terminal devices.

FIG. 7 shows a schematic configuration diagram of the wireless terminal device 2.
As illustrated in FIG. 7, the wireless terminal device 2 includes a control unit 20, a storage unit 21, a memory 22, a startup timer 23, a power supply control unit 24, a display control unit 25 a, a display unit 25 b, a wireless transmission unit 26, and wireless reception. A unit 27, a SW (switching unit) 28, an antenna 29, and the like are provided, and each unit is electrically connected. The wireless terminal device 2 includes a battery B, and power is supplied from the battery B to each unit in response to a control signal from the power supply control unit 24.

  The control unit 20 includes a CPU, a ROM, a RAM, and the like, reads out various programs stored in the storage unit 21, various programs and tables and data specified from various tables and data, and stores them in the RAM or the storage unit 21. In the work area, execute various processes in cooperation with the above program, store the processing results in a predetermined area of the RAM or storage unit 21, and instruct each unit in the wireless terminal device 2, The overall operation of the wireless terminal device 2 is comprehensively controlled.

  Further, the control unit 20 executes a wireless connection mode switching process program and various necessary data stored in the storage unit 21 and executes a wireless connection mode switching process, and functions as a second control unit.

  In the wireless connection mode switching process, when the first instruction signal is received from the wireless relay device, the wireless connection mode of the wireless terminal device is switched from the non-beacon mode to the beacon mode, and then switched to the beacon mode. When the instruction signal is received, the wireless connection mode is switched from the beacon mode to the non-beacon mode.

  The storage unit 21 is composed of a non-volatile memory that can be electrically erased and rewritten, such as a magnetic or optical recording medium or a semiconductor, and is provided in the wireless terminal device 2 or is detachable. It is to be attached. The storage unit 21 stores in advance various programs executed by the control unit 20 and various tables and data used in these programs.

  The memory 22 is configured by a nonvolatile memory that can be electrically erased and rewritten. The memory 22 stores terminal identification information (for example, node address) for identifying itself, received data, and the like.

  The activation timer 23 is a timer that measures an arbitrary activation timing set in advance or the activation timing calculated by the control unit 20, and outputs an activation timing signal indicating that the activation timing has been reached to the control unit 20. To do.

  The power control unit 24 controls the power supply of the entire wireless terminal device 2 in accordance with an instruction from the control unit 20, and supplies power from the battery B to each unit in the wireless terminal device 2.

  The battery B is, for example, a primary battery such as an alkaline battery or a manganese battery, or a secondary battery such as a nickel cadmium battery, a nickel hydrogen battery, or a lithium ion battery.

  The display control unit 25a displays various information on the display unit 25b in accordance with the display instruction input from the control unit 20.

  The display unit 25b is configured by an LCD (Liquid Crystal Display), an EL (Electro Luminescence) display, or the like, and displays various screens on the display according to a signal input from the display control unit 25a.

  The wireless transmission unit 26 includes a modulation circuit, an RF (Radio Frequency) circuit, and the like, adjusts the transmission power of the packet, encodes data to be transmitted in accordance with an instruction from the control unit 20, and transmits the packet. The packet is modulated, and the packet is transmitted to the wireless relay device 1 via the antenna 29.

  The wireless reception unit 27 includes a demodulation circuit, an RF circuit, and the like, and is obtained by adjusting the reception sensitivity of the packet, demodulating the packet received via the antenna 29, and analyzing the demodulated packet. The data is output to the control unit 20.

  The SW 28 is provided between the antenna 29 and the wireless transmission unit 26 or the wireless reception unit 27, and transmits a packet from the wireless transmission unit 26 or receives a packet from the antenna 29 in accordance with an instruction from the control unit 20. Switch.

  The antenna 29 transmits a packet according to the set transmission power or receives a packet according to the set reception sensitivity. The wireless transmitter 26, the wireless receiver 27, the SW 28, and the antenna 29 implement a second communication unit that performs wireless communication with the wireless relay device.

Next, the operation of the present embodiment will be described.
FIG. 8 and FIG. 9 show flowcharts of broadcast execution processing executed in the wireless relay device 1. 8 and 9 are executed by the cooperation of the control unit 10 and each unit in the wireless relay device 1.

  When executing the broadcast, the control unit 10 first sets a beacon frame (step S1). The setting of the beacon frame in step S1 is to set frame pending = 0 and pending address specification = 0.

  The control unit 10 causes the wireless transmission unit 14 to transmit the beacon signal set in step S1 (step S2), and determines whether all the wireless terminal devices have been switched from the non-beacon mode to the beacon mode (step S3).

  The control part 10 acquires the terminal information contained in the data request signal received from the wireless terminal device which received the message signal containing a beacon switching instruction | indication after execution start of this process. In step S3, when terminal information corresponding to all terminal information stored in the terminal information memory 12 is acquired, it is determined that all wireless terminal devices have switched from the non-beacon mode to the beacon mode. .

  When all the wireless terminal devices have not switched from the non-beacon mode to the beacon mode (step S3; NO), the control unit 10 determines whether or not a data request signal has been received from the wireless terminal device in the non-beacon mode ( Step S4).

  When the data request signal is not received from the wireless terminal device in the non-beacon mode (step S4; NO), the control unit 10 proceeds to the process of step 8.

  When the data request signal is received from the wireless terminal device in the non-beacon mode (step S4; Yes), the control unit 10 transmits an ACK signal (step S5) and transmits a message signal including a beacon switching instruction (step S6). ).

  The control unit 10 determines whether or not an ACK signal has been received from the wireless terminal device that has received the message signal transmitted in step S6 (step S7). If no ACK signal has been received (step S7; NO), The process returns to step S7.

  Step S4: After NO or when an ACK signal is received (step S7; Yes), the control unit 10 determines whether it is a beacon transmission timing (step S8). When it is not beacon transmission timing (step S8; NO), the control unit 10 returns to the process of step S4. When it is beacon transmission timing (step S8; Yes), the control part 10 returns to the process of step S2.

  When all the wireless terminal devices are switched from the non-beacon mode to the beacon mode (step S3; YES), it is determined that all the wireless terminal devices have been switched to the beacon mode (step S9).

  The processing from step S1 to S9 is processing for switching the wireless terminal device in the non-beacon mode to the beacon mode by the wireless relay device.

  After step S9, the control unit 10 changes the setting of the beacon frame (step S10). The beacon frame setting change in step S10 is to set frame pending = 1 and pending address specification = 0.

  The control unit 10 sets broadcast data (step S11). In step S11, for example, the destination address in the address area of the data frame is set to the broadcast address (0xFFFF), and data to be transmitted when broadcasting to the data payload is stored.

  The control part 10 discriminate | determines whether it is beacon transmission timing after step S11 (step S12), and when it is not beacon transmission timing (step S12; NO), it returns to the process of step S12.

  When it is beacon transmission timing (step S12; YES), the control unit 10 causes the beacon signal set in step S10 to be transmitted by the wireless transmission unit 14 (step S13), and the broadcast data set in step S11 is transmitted to the wireless transmission unit 14. (Step S14).

  The control unit 10 determines whether or not all data to be broadcast has been transmitted as broadcast data (step S15). When transmission of all data to be broadcast is not completed as broadcast data (step S15; NO), the control unit 10 returns to the process of step S11.

  When transmission of all broadcast data is completed as broadcast data (step S15; YES), the control unit 10 determines that transmission of broadcast data is complete (step S16).

  The processing from step S10 to S16 is processing for transmitting broadcast data to the wireless terminal device switched to the beacon mode by the wireless relay device.

  After step S16, the control unit 10 changes the setting of the beacon frame (step S17). The beacon frame setting change in step S17 is to set frame pending = 0 and pending address specification = 0.

  The control part 10 discriminate | determines whether it is beacon transmission timing after step S17 (step S18), and when it is not beacon transmission timing (step S18; NO), it returns to the process of step S18.

  When it is beacon transmission timing (step S18; YES), the control unit 10 causes the wireless transmission unit 14 to transmit the beacon signal set in step S17 (step S19), and whether or not a message signal is received from the wireless terminal device. Is determined (step S20). The message signal received in step S20 includes information indicating that switching from the beacon mode to the non-beacon mode has been completed.

  When a message signal is not received (step S20; NO), the control unit 10 determines whether or not it is a beacon transmission timing (step S21). When it is not beacon transmission timing (step S21; NO), the control unit 10 returns to the process of step S20. When it is beacon transmission timing (step S21; YES), the control unit 10 returns to the process of step S19.

  When the message signal is received (step S20; YES), the control unit 10 transmits an ACK signal (step S22), and determines whether all the wireless terminal devices have been switched from the beacon mode to the non-beacon mode (step S22). S23).

  The control unit 10 acquires terminal information included in the message signal received in step S20. In step S23, information indicating that the switching from the non-beacon mode to the beacon mode is completed from the wireless terminal device corresponding to the terminal information corresponding to all the terminal information stored in the terminal information memory 12 is included. When the message signal is received, it is determined that all the wireless terminal devices are switched from the beacon mode to the non-beacon mode.

  When all the wireless terminal devices are not switched from the beacon mode to the non-beacon mode (step S23; NO), the control unit 10 proceeds to the process of step S21. When all the wireless terminal devices are switched from the beacon mode to the non-beacon mode (step S23; YES), the control unit 10 stops the transmission of the beacon signal (step S24) and ends this process.

  FIG. 10 shows a flowchart of the wireless connection mode switching process executed in the wireless terminal device 2. Note that the process shown in FIG. 10 is executed by the cooperation of the control unit 20 and each unit in the wireless terminal device 2.

  The control unit 20 activates each unit at a preset arbitrary timing (Wake up) (Step S31), and causes the wireless transmission unit 26 to transmit a data request signal to the wireless relay device 1 (Step S32).

  The control unit 20 determines whether or not an ACK signal has been received from the wireless relay device that has transmitted the data request signal (step S33). If no ACK signal has been received (step S33; NO), the process of step S33 is performed. Return to.

When the ACK signal is received (step S33; YES), the control unit 20 determines whether or not a message signal including a beacon switching instruction has been received (step S34). When the message signal including the beacon switching instruction is not received (step S34; NO), the control unit 20 receives the data signal (step S35), transmits the ACK signal (step S36), and shifts to the sleep state. (Step S37).
That is, steps S31 to S37 are general non-beacon mode processing.

  When a message signal including a beacon switching instruction is received (step S34), the control unit 20 switches the wireless connection mode to the beacon mode (step S38), transmits an ACK signal (step S39), and waits for reception of a beacon signal. (Step S40).

  The control unit 20 determines whether or not a beacon signal has been received (step S41). If no beacon signal has been received (step S41; NO), the process returns to step S41.

  When a beacon signal is received (step S41; YES), the received beacon signal is inspected (step S42). In step S42, activation timing is calculated based on the received beacon signal, and frame pending and pending address specification values are analyzed.

  The control unit 20 determines whether or not the broadcast is completed based on the received beacon signal (step S43). In step S43, the beacon signal received immediately before the beacon signal received in step S41 has frame pending = 1 and the pending address specification = 0, but the beacon signal received in step S41 has frame pending = 0, pending. When the address specification = 0, it is determined that the broadcast is complete.

  When the broadcast has not been completed (step S43; NO), the control unit 20 determines whether or not the broadcast data is waiting to be received (step S44). In step S44, when the frame pending = 1 and the pending address specification = 0, it is determined that the broadcast data is waiting to be received.

  If it is not standby for receiving broadcast data (step S44; NO), the control unit 20 proceeds to the process of step S46. When it is standby for receiving broadcast data (step S44; YES), the control unit 20 waits for reception of broadcast data and determines whether broadcast data has been received (step S45).

  When broadcast data is not received (step S45; NO), the control unit 20 returns to the process of step S45.

  Step S44: After NO or when broadcast data is received (step S45; YES), the control unit 20 shifts to a sleep state (step S46).

  The control unit 20 determines whether or not it is the activation timing calculated in step S42 (step S47). If it is not the activation timing (step S47; NO), the control unit 20 returns to the process of step S47. When it is an activation timing (step S47; YES), the control unit 20 activates each unit (step S48), and returns to the process of step S40.

  Step S34; YES to step S48 are processes in the beacon mode when the wireless terminal device in the non-beacon mode is switched to the beacon mode.

  When the broadcast is completed (step S43; YES), the control unit 20 switches the wireless connection mode to the non-beacon mode (step S49), and sends a message signal including information indicating the completion of switching from the beacon mode to the non-beacon mode. Transmit (step S50).

  The control unit 20 determines whether or not an ACK signal has been received from the wireless relay device that has transmitted the message signal in step S50 (step S51). If no ACK signal has been received (step S51; NO), step The process returns to S51.

  When the ACK signal is received (step S51; YES), the control unit 20 shifts to the sleep state (step S52) and ends this process.

  Steps S43 to S52 are processing in the non-beacon mode when the beacon mode is switched to the non-beacon mode.

An example of the present embodiment will be described with reference to FIGS.
11 to 13, it is assumed that three wireless terminal devices (first to third wireless terminal devices) are connected to the wireless relay device. Assume that the wireless relay device performs broadcasting to the first to third wireless terminal devices.

  FIG. 11 is a sequence diagram illustrating a process in which the first to third wireless terminal devices are switched from the non-beacon mode to the beacon mode by the wireless relay device.

  As shown in FIG. 11, the wireless relay device first periodically transmits a beacon signal set to frame pending (FP) = 0 and pending address specification (PA) = 0 (step S101).

  The first wireless terminal device is activated at an arbitrary activation timing (step S102), and transmits a data request signal to the wireless relay device. The wireless relay device transmits an ACK signal to the first wireless terminal device and transmits a message signal including a beacon switching instruction. When receiving the message signal after receiving the ACK signal from the wireless relay device, the first wireless terminal device switches the wireless connection mode from the non-beacon mode to the beacon mode and transmits the ACK signal to the wireless relay device. Then, the first wireless terminal device waits for reception of the next beacon signal transmitted from the wireless relay device (step S103).

  Since all of the first to third wireless terminal devices have not switched to the beacon mode, the wireless relay device transmits a beacon signal with frame pending = 0 and pending address specification = 0 again at the beacon transmission timing (step S104).

  When receiving the beacon signal, the first wireless terminal device shifts to the sleep state because frame pending = 0 and pending address specification = 0 of the received beacon signal (step S105). Thereafter, the first wireless terminal device performs activation, beacon reception standby, beacon inspection, and sleep processing in accordance with the timing at which the beacon signal is transmitted.

  When the second wireless terminal device and the third wireless terminal device are activated at an arbitrary timing, the beacon mode is switched similarly to the first wireless terminal device. That is, it starts according to the timing at which the beacon signal is transmitted, and enters the sleep state after receiving the beacon signal.

  FIG. 12 is a sequence diagram illustrating a process in which broadcasting is executed after the first to third wireless terminal devices are switched to the beacon mode by the wireless relay device.

  The wireless relay device transmits a beacon signal whose setting has been changed to frame pending (FP) = 1 and pending address specification (PA) = 0 (step S111). Also, broadcast data is transmitted after the beacon signal is transmitted (S112).

  When receiving the beacon signal, the first to third wireless terminal apparatuses wait for the reception of broadcast data because frame pending of the received beacon signal = 1 and pending address specification = 0 (step S113). Thereafter, the first to third wireless terminal devices receive the broadcast data and enter a sleep state (S114).

  Until transmission of all data to be broadcast is completed as broadcast data, the processes of S111 to S114 are continuously repeated over a plurality of beacon periods.

  FIG. 13 is a sequence diagram illustrating processing in which the first to third wireless terminal devices are switched from the beacon mode to the non-beacon mode by the wireless relay device after transmission of broadcast data is completed.

  The wireless relay device transmits a beacon signal whose setting has been changed to frame pending = 0 and pending address specification = 0 (step S121).

  The first to third wireless terminal apparatuses detect that the frame pending of the received beacon signal has changed from 1 to 0 and the pending address specification has changed from 0 to 0, and determine that the broadcast has been completed. Then, each of the first to third wireless terminal devices switches the wireless connection mode from the beacon mode to the non-beacon mode, and transmits a message signal (step S122).

  When receiving the message signal from the first to third wireless terminal devices, the wireless relay device transmits an ACK signal. When receiving the ACK signal for the transmitted message signal, the first to third wireless terminal apparatuses transition to the sleep state (step S123).

  When the wireless relay device receives the message signal from all of the first to third wireless terminal devices and determines that all of the first to third wireless terminal devices have switched from the beacon mode to the non-beacon mode, the wireless relay device stops transmitting the beacon signal. .

  As described above, according to the present embodiment, when a wireless relay device performs broadcasting, after all wireless terminal devices in non-beacon mode are temporarily switched to beacon mode, broadcast data is transmitted, and after the broadcast is completed. By switching all the wireless terminal devices to the non-beacon mode and returning to the original wireless connection mode, all the wireless terminal devices that are periodically activated according to the beacon cycle can receive the same broadcast data.

For this reason, it is not necessary for all the wireless terminal devices to be kept in the reception standby state until the transmission of the broadcast data is completed, and power saving of the wireless terminal device can be achieved.
In addition, since the same broadcast data is received by the wireless terminal device at the same time, an increase in the number of wireless terminal devices and an increase in the size of data to be transmitted increase the network traffic and decrease the communication efficiency. Can be prevented.
Therefore, when broadcasting, it is possible to prevent an increase in network traffic and a decrease in communication efficiency while suppressing power consumption of the wireless terminal device.

  Further, a beacon switching instruction is included in a message signal transmitted after a beacon signal (frame pending = 0, pending address specification = 0) indicating that there is no data to be transmitted to all of the plurality of wireless terminal devices. Thus, it is possible to realize an instruction to switch the wireless connection mode from the non-beacon mode to the beacon mode using the signal used in the beacon mode without changing the wireless communication standard.

  Also, by using a beacon signal for broadcasting (frame pending = 1, pending address specification = 0) and a beacon signal (frame pending = 0, pending address specification = 0) transmitted after the broadcast is completed. Even without changing the wireless communication standard, an instruction to switch from the beacon mode to the non-beacon mode can be realized using the beacon signal.

  Further, all of the plurality of wireless terminal devices are non-based based on the terminal information included in the data request signal of the wireless terminal device that has received the message signal including the beacon switching instruction and the terminal information stored in the terminal information memory. It can be determined that the beacon mode is switched to the beacon mode.

1 wireless relay device 2 wireless terminal device 10 control unit 11 storage unit 12 terminal information memory 13 beacon transmission timer 14 wireless transmission unit 15 wireless reception unit 16 SW
17 I / F unit 18 Buffer 19 Antenna 20 Control unit 21 Storage unit 22 Memory 23 Startup timer 24 Power supply control unit 25a Display control unit 25b Display unit 26 Wireless transmission unit 27 Wireless reception unit 28 SW
29 Antenna A Wireless communication system B Battery B1 MHR area B2 MAC payload area B3 MFR area B11 Frame control B11a Frame type B11b Frame pending B11c ACK request B11d PAN ID compression B11e Frame version B12 Address area B21 SS
B22 GTS field B23 PA field B23a Pending address specification area B23a1 Number of Short Address Pending area B23a2 Number of Extended Address Pending area B23b Address list B24 Beacon payload D1 MHR area D2 MAC payload area D3 MFR area D11 Frame control D12 Address area D12a Destination PAN ID area D12b Destination address area D12c Source PAN ID area D12d Source address area D21 Data payload N Communication network

Claims (5)

In a wireless communication system comprising a plurality of wireless terminal devices and a wireless relay device and performing wireless communication in a non-beacon mode,
The wireless relay device is
A first communication unit that performs wireless communication with the plurality of wireless terminal devices;
When broadcasting to the plurality of wireless terminal devices, a first instruction signal for switching a wireless connection mode from the non-beacon mode to the beacon mode is transmitted, and the plurality of wireless terminal devices change from the non-beacon mode to the beacon mode. A first control unit that transmits the second instruction signal that causes the broadcast to be performed after switching, and switches from the beacon mode to the non-beacon mode after the broadcast is completed,
The wireless terminal device
A second communication unit for performing wireless communication with the wireless relay device;
When the first instruction signal is received from the wireless relay device, the wireless connection mode is switched from the non-beacon mode to the beacon mode, and the second instruction signal is received after switching to the beacon mode, A second control unit that switches the wireless connection mode from the beacon mode to the non-beacon mode,
A wireless communication system. The first instruction signal is:
Included in a message signal transmitted after a beacon signal indicating that there is no data to be transmitted to the plurality of wireless terminal devices;
The wireless communication system according to claim 1. The second instruction signal is:
A beacon signal transmitted after the beacon signal for performing the broadcast is transmitted and the broadcast is completed,
The wireless communication system according to claim 1, wherein The wireless relay device is
A terminal information storage unit for storing terminal information indicating information unique to each of the plurality of wireless terminal devices to be connected;
The first controller is
When the terminal information included in the data request signal of the wireless terminal device that has received the first instruction signal is acquired and the terminal information corresponding to the terminal information stored in the terminal information storage unit is acquired, It is determined that the plurality of wireless terminal devices are switched from the non-beacon mode to the beacon mode.
The wireless communication system according to any one of claims 1 to 3. In a wireless communication method in which a plurality of wireless terminal devices and a wireless relay device perform wireless communication in a non-beacon mode,
When the wireless relay device broadcasts to the plurality of wireless terminal devices, the wireless relay device transmits a first instruction signal for switching a wireless connection mode from the non-beacon mode to a beacon mode;
A second step of switching the wireless connection mode from the non-beacon mode to the beacon mode when the wireless terminal device receives the first instruction signal;
The wireless relay device causes the plurality of wireless terminal devices to perform the broadcast after switching from the non-beacon mode to the beacon mode, and to switch from the beacon mode to the non-beacon mode after the broadcast is completed. A third step of transmitting an instruction signal;
A fourth step of switching the wireless connection mode from the beacon mode to the non-beacon mode when the wireless terminal device receives the second instruction signal after switching to the beacon mode;
A wireless communication method characterized by comprising:

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